In U.S. Pat. No. 4,219,559 there are described a number of antihistaminic 1-substituted N-heterocyclyl-4-piperidinamines. In U.S. Pat. Nos. 4,556,660; 4,634,704; 4,695,575 and 4,588,722 there are described a further series of N-heterocyclyl-4-piperidinamines as antihistaminics and serotonin antagonists. In EP-A-0,151,826; 0,206,415; 0,282,133; 0,295,742 and 0,297,661 there are disclosed a number of structurally related compounds as antihistaminics and serotonin antagonists.
The compounds of the present invention differ therefrom by the fact that they invariably are substituted with a 2-aminopyrimidinone containing moiety.